Smartphones and tablets have moved from a gaming niche to the main market mover.Just over two years ago, we looked back at analyst reports for the 2015 gaming market and highlighted the surprising finding that the PC was actually the world's most important gaming platform from a raw revenue perspective. But we warned that continued double-digit growth in the mobile market meant the PC's market dominance wouldn't last forever.

Fast-forward to the forecast for the 2018 global game market, and things could scarcely look more different. Newzoo's 2018 Global Games Market Forecast now predicts that mobile games will make up a slim majority (51 percent) of all worldwide gaming revenue this year (including smartphones and tablets, but not dedicated gaming handhelds). That's up from 34 percent in 2015 and just 18 percent in 2012. Console and PC games will split the remainder of the pie relatively evenly in 2018, at 25 percent and 24 percent of worldwide spending, respectively.

The growth of the mobile market doesn't show any signs of stopping, either: by 2021, Newzoo estimates that 59 percent of all gaming spending will go to mobile platforms, with console and PC games dividing up the scraps.

If you had to sum up that change in one word, it could easily be "Asia," which now represents 52 percent of the global games market (when paired with Oceania). China alone is now responsible for 28 percent of all gaming spending in the world, up from 24 percent in 2015. Mobile gaming is overrepresented in the world's biggest gaming market, responsible for 61 percent of all Chinese gaming revenue and poised to grow to 70 percent by 2021.

In Japan, meanwhile, overall spending on mobile games is nearly the same as in the United States, despite the country having one-third as many gamers overall. On a per-player basis, Japanese gamers spend about 50 percent more than their North American counterparts and 150 percent more than players in Europe, and Newzoo says that difference is particularly stark for mobile games.

While mobile game spending continues to grow around the world, Newzoo sees the market for PC games as somewhat saturated. "Some of the most popular [PC] titles are already operating at close to their full monetization potential and, at the same time, are unlikely to be displaced by new games soon," the analysts write. Race-to-the-bottom pricing on pay-to-play PC titles will also limit the growth of the PC market to a tepid 1.8 percent annually through 2021, Newzoo predicts, compared to 10.3 percent annual growth for mobile games in the same period.With numbers like these, it's no wonder that popular big-screen games like Fortnite and PUBG have been making the move to full-featured mobile versions. Newzoo sees the same trend cutting the still-lucrative browser-based MMO market (which is huge in Asia) to half its current size by 2021, as players shift to playing on their phones instead.

Console and PC players shouldn't worry that their chosen platforms will be withering away in the next few years or anything. On the contrary, both segments will continue to grow in absolute revenue terms for the forseeable future, Newzoo predicts. But the continued, explosive growth of mobile spending probably means the biggest international entertainment conglomerates will be focusing an increasing amount of resources on games that can be played by the two-billion-plus people with a smartphone in their pocket, and not just by the relatively smaller number with access to a gaming PC or console.Kyle Orland